1) Technical Field
The subject invention relates to a mechanical device for automatically taking-up slack in a control cable of a motion transmitting system.
2) Description of the Prior Art
Conventional take-up devices used for taking-up slack in control cables are well known in the art. For it is recognized that, in many motion transmitting control systems, it is desirable to include some form of a take-up device in relation to the control cable to take-up any slack generated in the motion transmitting system. It is understood that excessive slack in the control cable may significantly diminish the operating efficiency of the motion transmitting system.
Many conventional devices implemented to take-up slack in a control cable are deficient in that the operation of taking-up slack is not automatic. Nor is the operation of taking-up slack with these take-up devices continuous. That is to say that many conventional take-up devices do not automatically account for the tendency of the control cable in a motion transmitting system to return to a slackened position. For example, although a common turnbuckle takes-up slack in a control cable, the operation is not automatic because the turnbuckle requires manual adjustment. Furthermore, in the time interval between manual adjustment of the turnbuckle, the control cable returns to the slackened position and the operating efficiency of the motion transmitting system is diminished due to the excessive slack in the control cable. Examples of such conventional take-up devices are shown in U.S. Pat. Nos. 2,403,828, 2,813,733, and 5,702,196.
In a similar conventional manner simple extension springs in combination with a linear ratchet mechanism have been employed to take-up slack in a control cable. In such conventional devices, the extension spring takes-up slack in the control cable, and the linear ratchet mechanism performs a mechanical locking function to prevent the control cable from returning to the slackened position. However, in the time interval between increasing mechanical locks of the linear ratchet mechanism, the control cable returns to the slackened position. In sum, such locking linear ratchet mechanisms are deficient because they do not account for the control cables tendency to return to the slackened position in between increasing mechanical locks of the control cable.
Due to the inefficiencies identified in conventional take-up devices, it is desirable to implement a take-up device that automatically takes-up slack in a control cable while accounting for the continuous tendency of the control cable to return to the slackened position by preventing this return from taking place.